Answering Questions on 'The Human Family Tree'

On Sunday, Aug. 30, National Geographic Channel premieres a special called
"'The Human Family Tree," which looks at how genetic testing is allowing scientists to trace human migration patterns over thousands of years, all the way back to humanity's origins in Africa (which, in case your mind drifts, the special repeats about 15 or so times).

If you visit the homepage, you can even find out how to
test your own DNA -- the maternal lineage for women, and the maternal or paternal lineage for men.

Check out this cool migration map (double-click for a larger view):

I found out that I'm part of
Haplogroup T (mitochondrial DNA), which originated around the Fertile Crescent and then spread to Europe.

I got confused because, according to what I had read in Wikipedia, T was part of JT, which also spawned J. So all those Haplogroup J relations bombarding me with requests for cash, back off! You're not coming to the HapT reunion picnic (it's a big bunch, so the hot rumor is that we're renting Monaco for the day).

Anyway, I did an email Q&A with population geneticist
Spencer Wells, who's featured in the
special. And away we go ...

Q: I passed the info to my mother, who does genealogy, and it didn't mean a great deal to her, because it's so generalized. How can you make information like this more relevant to people?

A: Well, your results reveal your deep ancestry along a single line of direct descent (paternal or maternal) and show the migration paths your ancestors followed thousands of years ago. We pick up where genealogy leaves off -- in that we go much further back! We test for ancestral lineages and their associated migrations on an anthropological timescale, meaning they provide a window back hundreds, thousands, even tens of thousands of years ago. The genetic markers we study place everyone on the greater human family tree, rather than the smaller family tree we are generally more familiar with. Your individual results may confirm your expectations of what you believe your deep ancestry to be, or you may be surprised to learn a new story about your genetic background.

Q: Which results have surprised you most in your study, and which confirmed what you already believed to be true?

A: I'm still blown away by how recently our species emerged from
Africa
-- only in the past 60,000 years. It's the blink of an eye in an evolutionary sense, and underscores how superficial all of our differences really are. We're all basically African cousins.

Q: How can women trace their paternal ancestors?

A: Females do not possess a Y chromosome, and therefore may only have the mitochondrial DNA test performed (which traces their maternal lineage). However, if you are a female and would like to learn about your paternal lineage, then a male relative--such as a father, a brother, or a paternal blood relative of your father's, such as his brother--can test his Y-chromosome DNA. The results will reveal a female's paternal lineage.

Q: Are other scientific specialties - such as anthropology, archaeology or sociology - able to make use of what you have learned about human migratory patterns?

A: We hope they are all able to apply our research as we have studied and pulled from each of those fields to provide context for the genetic results.

Q: What do you most hope people will take away from the project?

A: That there literally is a single human family tree, and we're all carrying part of the story inside ourselves. Our human species reflects a mixture of ethnic backgrounds and cultural traditions. In a place like
Queens
,
New York
, more than half the population is foreign-born, and there are more than 150 different languages spoken there. As we showed in the film, the diversity we see there represents a microcosm of the world. Yet when we test their genetic data, we learn that they - like all humans - are 99.9% similar. We hope viewers of the film take away that there literally is a single human family tree, and we're all carrying part of the story inside ourselves.

Q: What's the next step for your research?

A: We anticipate publications from the analysis of this data will continue for several years into the future.